Estimating the empirical entry model developed by Bresnahan and Reiss(1991), this paper examines the extent to which the entry of a large discountstore into a region changes the competitive conduct. In order to calculate theentry thresholds, we utilize county-level geographic information of three largediscount stores: Emart, Homeplus, and Lottemart. The analysis shows that alarge discount retailer in Korea receives a small amount of excess profits frommonopolistic or oligopolistic market. The entry of an additional large discountretailer promotes competition, but the effect on the degree of competition isnot substantial.